1. Field of the Invention
The present invention relates to a vehicle height adjustment apparatus that adjusts a vehicle height of a motorcycle.
2. Description of Related Art
In recent years, an apparatus is proposed which increases the vehicle height of a motorcycle while the motorcycle is travelling, and decreases the vehicle height in order for an occupant to easily get on and off the motorcycle at a stop.
For example, a vehicle height adjustment apparatus disclosed in JP-B-H08-22680 has the following configuration. That is, a rear arm is pivotably supported by a rear portion of a vehicle frame of the motorcycle, and a rear wheel is supported in a rear end of the rear arm via a vehicle axle. A hydraulic shock absorbing apparatus is disposed between the rear arm and the vehicle frame via a link mechanism. The hydraulic shock absorbing apparatus has a hydraulic attenuator and a shock absorbing spring. A lid is fitted into a cylinder head aperture, and also functions as a bracket for attachment of a cylinder. A support tube is fixed to the lid while being freely fitted in the circumference of the cylinder. A cylindrical spring seat is inserted in a fitting yet slidable manner into the cylinder and the support tube. The spring seat is intended to support the shock absorbing spring on the opposite side of a bracket of a piston rod. A working oil chamber is formed on an inner side of the support tube. The vehicle height adjustment apparatus pushes the spring seat downwardly against the shock absorbing spring, and extends an oil pressure attenuator by changing the oil pressure of the working oil chamber. Accordingly, a gap between the rear arm and the frame is increased, and thus the vehicle height is increased.